Sharing resources in a networked computer system, such as processors, computer memories, network bandwidth and data storage facilities, among clients, e.g., virtual machines (VMs), running on the system can increase efficiency by reducing maintenance and operating costs, allowing flexibility with respect to individual resource usage, and simplifying resource management. With respect to shared storage, the benefits include data consolidation, universal access to data, ease of storage management, and support for live migration of virtualized environments.
In order to further reduce the operating cost of the networked computer system, a power management technique may be used to minimize power consumption of host computers running on the networked computer system during periods of low resource utilization. This can be achieved by selectively migrating clients onto fewer host computers during periods of low resource utilization and powering off the unneeded host computers, i.e., the host computers without any clients in operation. However, since load conditions can change suddenly over time, it may be difficult to make the appropriate decisions regarding client migration and powering-down the unneeded host computers.